1. Field
The invention relates to a polyaxial bone anchoring device. The anchoring device includes an anchoring element having a shank and a head and further includes a receiving part for coupling the anchoring element to a rod. The receiving part has an upper member and a lower member connectable to the upper member and at least one clamping member that is configured to hold the anchoring element in the receiving part when the upper and lower members are assembled. The polyaxial bone anchoring device is particularly suitable for providing a modular system.
2. Description of Related Art
WO 2011/077511 A1 describes a spine fixing device provided with a screw and also with a head to which the screw and a rod can be fixed. The head is provided with a head body and a fixing nut, which fixes the screw to the head. When mounted to the head body, the fixing nut holds the screw. The state of mounting of the fixing nut to the head body is adapted to be switchable between a first state, in which the screw is held so as to be able to pivot and a second state, in which the screw is held, so as not to be able to pivot.